The present invention relates in general to reducing the self discharge of thermal batteries, and in particular to reducing the self discharge of thermal batteries having a high conductivity electrolyte salt.
Thermal batteries that use the high conductivity electrolyte salt LiCl-LiBR-LiF eutectic are more subject to self discharge during their storage lifetimes than are the traditional thermal batteries that use the LiCl-KCl eutectic. For the traditional LiCl-KCl thermal batteries, the cold (unactivated) voltage is usually less than 10 millivolts for a nominal 30 volt battery when measured with a 10 megohm input meter. For LiCl-LiBr-LiF electrolyte thermal batteries, cold voltage measured during storage with a 10 megohm input is typically several volts and may be a substantial fraction (30 to 60 percent) of the activated voltage. The much larger cold voltage of LiCl-LiBr-LiF batteries may permit significantly more self discharge during storage for many fuze applications.